The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines draw air into an intake manifold through an inlet system that may be regulated by a throttle. The air in the intake manifold may be distributed to a plurality of cylinders through a plurality of intake valves, respectively. The air may be combined with fuel to create an air/fuel (A/F) mixture. The A/F mixture may be combusted within the cylinders to drive pistons that rotatably turn a crankshaft generating drive torque. Exhaust gas resulting from combustion may be expelled from the cylinders through a plurality of exhaust valves, respectively, and into an exhaust manifold.
The intake and exhaust valves may be actuated by one or more camshafts. Alternatively, however, the intake and exhaust valves may be electrically controlled using hydraulic actuators (“electro-hydraulic” control). The electro-hydraulic control of intake and exhaust valves of an engine may be referred to as electro-hydraulic valve actuation (EHVA). Therefore, an EHVA engine may not include camshafts (i.e., a cam-less engine). More specifically, an EHVA system may control hydraulic pressure (i.e., pressure of a hydraulic fluid) to selectively engage/disengage hydraulic actuators that enable/disable intake and/or exhaust valves.